A question of originality

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I hope Craig chimes in there are issues with the new shoe materials eating up the new drums. He was telling me about it last time we met.
@mobileparts

There are no "issues" with new shoe materials. They work better. "Working better" means that they have a higher coefficient of friction. A higher coefficient of friction means that they also grab onto the drums better, which does cause them to wear the drums faster. That's literally how brakes work. They're a friction device. The more friction you create, the faster you will stop, and the faster your brake parts will wear out. So yeah, modern shoe materials have higher coefficients of friction, so your car stops faster. That's a GOOD thing because stopping safely is important. Hell it's the most important thing your car does. Doesn't matter how fast you are if you can't stop.

If you're more worried about wearing out your drums than you are about stopping your car quickly and safely, you've crossed over into museum land. As in, stay off the road. Because getting your original drums to last forever compromises your safety and the safety of everyone else on the road with you.

As far as mobileparts goes, he's not an unbiased source of information. He'd love for you to buy his obsolete, underperforming asbestos pads because he has a whole warehouse full of them. They don't work better. They last longer because they have a lower friction coefficient. Sure, your drums will last longer, but your car won't stop as well. And oh right, there's the whole cancer causing asbestos dust thing. If you need original parts for your concourse judged show horse that never sees the street- great. If you want to actually drive and STOP your car it's a terrible idea, because there are better brakes out there for actually stopping your car.
 
Drums are especially troubling because many are not available anymore. When you turn a drum, you of course make it larger. But the shoes are designed for a specific diameter, so when you use shoes in an oversize drum, not all the lining makes contact, and the center of the shoe has to work harder, which will glaze it and vastly reduce effectiveness. "Back in the day" you could have shoes arced, or in some cases shims intalled between lining and shoe. "Good luck" finding anyone with either capability.

Like this:
Drum Brakes
View attachment 1715670226

Arcing machine:

View attachment 1715670228

Ends up like this:

View attachment 1715670229

Corvette%2520Brakes%25208-28-13%2520009.JPG
I worked at a shop in my younger years and worked on all the Hillsborugh Sheriff cars. They would get between 3000-12000 miles on a brake job. I learned the art of using a rearcing tool. Years ago you could by 1,2 over size shoes.
 
There's a nice little break down of a bunch of brake pad/shoe compounds here. Yes, it's a site mostly for MGB's, but the brake materials covered are all relevant. It covers carbon metallic, carbon kevlar, ferro carbon, and ceramic materials. It's a bit of a read so I'll just link it here, scroll down until you get to the picture of the brake rotor.

British Automotive

Worth posting here is the info on asbestos linings. Their issues are well known, and I'm not just talking about cancer. And much better stuff now exists. From the British Automotive site-

"First of all, brake pads containing asbestos are a thing of the past. I only mention them here as a reminder of their past performance, rather like a belated obituary.

Brake pads containing asbestos were capable of absorbing lots of heat without burning, however, they would begin to glaze as low as 250 degrees F, thereby reducing their coefficient of fiction (COF), and as temperatures reached 350 degrees F, fading would become apparent. Sustained high temperatures would form a glaze deep enough into the pad material that they would, in many cases, never recover. On top of this we knew how inefficient this material became when wet. It is estimated that asbestos brake pads under these conditions lost almost 2/3 of their COF. "May they rest in peace."
"

There's also this article from Hemmings. A little lighter on data but it's a more main stream source.
https://www.hemmings.com/stories/2013/08/30/tech-101-how-to-choose-the-right-brake-friction-material

Bottom line is, asbestos sucks. And yes, I'm old enough to have used asbestos brake linings and semi-metallics on the same car. The fact is that there are compounds out there now that will stop your car faster. And that's all you should be worried about unless you park your car in a museum. Stopping faster is better, and since it's unlikely any of us are fitting ABS systems we need all the help we can get if we're out on the streets with modern cars.
 
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